Merge pull request #2963 from swagger-api/fix-callback-deser

fix ref callback deserialization

Author: frantuma

modules/swagger-core/src/main/java/io/swagger/v3/core/util/CallbackDeserializer.java

@@ -28,6 +28,8 @@ public Callback deserialize(JsonParser jp, DeserializationContext ctxt)
             // if name start with `x-` consider it an extesion
             if (childName.startsWith("x-")) {
                 extensions.put(childName, Json.mapper().convertValue(child, Object.class));
+            } else if (childName.equals("$ref")) {
+                result.$ref(child.asText());
             } else {
                 result.put(childName, Json.mapper().convertValue(child, PathItem.class));
             }

modules/swagger-core/src/test/java/io/swagger/v3/core/deserialization/JsonDeserializationTest.java

@@ -256,4 +256,33 @@ public void deserializeLongSchema() throws IOException {
         assertEquals(s.getEnum().get(1), 3147483647L);
         assertEquals(s.getEnum().get(2), 31474836475505055L);
     }
+
+    @Test(description = "Deserialize ref callback")
+    public void testDeserializeRefCallback() throws Exception {
+        String yaml = "openapi: 3.0.1\n" +
+                "info:\n" +
+                "  description: info\n" +
+                "paths:\n" +
+                "  /simplecallback:\n" +
+                "    get:\n" +
+                "      summary: Simple get operation\n" +
+                "      operationId: getWithNoParameters\n" +
+                "      responses:\n" +
+                "        200:\n" +
+                "          description: voila!\n" +
+                "      callbacks:\n" +
+                "        testCallback1:\n" +
+                "          $ref: '#/components/callbacks/Callback'\n" +
+                "      callbacks:\n" +
+                "        testCallback1:\n" +
+                "          $ref: '#/components/callbacks/Callback'\n" +
+                "components:\n" +
+                "  callbacks:\n" +
+                "    Callback:\n" +
+                "      /post:\n" +
+                "        description: Post Path Item\n";
+
+        OpenAPI oas = Yaml.mapper().readValue(yaml, OpenAPI.class);
+        assertEquals(oas.getPaths().get("/simplecallback").getGet().getCallbacks().get("testCallback1").get$ref(), "#/components/callbacks/Callback");
+    }
 }